This invention relates generally to the treatment of wood products with preservatives and, more particularly, to apparatus for treating packaged lumber for shipping.
Packaged lumber is conventionally treated with alkaline, penta-type or other liquid preservatives to prevent growth of mildew while enclosed in the hold of a ship. Most commonly, the preserving fluid is sprayed on the packages of lumber just prior to shipping. However, the sprays of most such fluids are highly irritating to humans and do not effectively penetrate the interior of the packages of lumber. A lumber-dipping system has been tried wherein a package of lumber, handled by a lift truck, is placed on a fork lift hoist positioned above a tank full of preserving fluid, chained down, sumbmerged in the tank, lifted out and then removed from the hoist by the lift truck. While this technique improves the penetration of preserving fluid into the package, it is wasteful and does not minimize the exposure of workers to the irritants in the preservative. When the package is removed from the hoist, the preserving fluid drips from the package onto the lift truck and its operator, and onto the ground. The drippings create an irritating and unhealthy working atmosphere for the lift truck and hoist operators. It would be preferable to minimize the amount of preserving fluid wasted and, further, to minimize the exposure of workers to either liquid or airborne preserving fluid, while effectively treating the packages of lumber.